Machine tool of the drill press type having multiple rotary tools



March 1954 F. G. BURG 2,670,636

MACHINE TOOL OF THE DRILL PRESS TYPE HAVING MULTIPLE ROTARY TOOLS 9 Sheets-Sheet 1 Filed June 10, 1948 umw INVENTOR.

nrmeA/EV March 2, 1954 k F. e. BURG 2, 7

v MACHINE TOOL OF THE DRILL PRESS TYPE HAVING MULTIPLE ROTARY TOOLS Filed June 10, 1948 9 Sheets-Sheet 2 I t it: 7

FEED a. 50426,

INVENTOR. M f4;

RTWENEV March 1954 F. G. BURG ,670,636

MACHINE TOOL OF THE DRILL PRESS TYPE HAVING MULTIPLE ROTARY TOOLS JNVEN TOR.

BY -xiwzw F77 EBA/E 7 March 2, 1954 URG 2,670,636

MACHINE TOOL OF T DRILL PRESS TYPE HAVING MULTIPLE ROTARY TOOLS 9 Sheets-Sheet 4 Filed June 10, 1948 F. G. BURG MACHINE TOOL OF THE DRILL PRESS TYPE March 2, 1954 HAVING MULTIPLE ROTARY TOOLS 9 Sheets-Sheet 5 Filed June 10, 1948 FQED G. 5086,

INVEN TOR.

March 2,, 1954 F. G. BURG 2, MACHINE TOOL OF THE DRILL PRESS TYPE HAVING MULTIPLE ROTARY TOOLS Filed June 10, 1948 v 9 Sheets-Sheet 6 aamwm F850 6- BUBG,

INVENTOR.

QTTO/QNEV March 2, 1954 BURG MACHINE TOOL OF THE DRILL PRESS TYPE HAVING MULTIPLE ROTARY TOOLS 9 Sheets-Sheet 7 Filed June 10, 1948 FEED 6- 31/96,

INVENTOR.

K Y BY nrroexvsy March 2, 1954 F. G. BURG 2,670,636 MAC I E TOOL OF THE DRILL PRESS TYPE VING MULTIPLE ROTARY TOOLS Filed June 10, 1948 9 Sheets-Sheet 8 a nu 1| INVENTOR.

March 2, 1954 F. G. BURG 2,670,636

MACHINE TOOL OF THE DRILL PRESS TYPE r HAVING MULTIPLE ROTARY TOOLS Filed June 10, 1948 iii a 3 2 9 Sheets-Sheet 9 eels/r204 50X TUOL SPEED CONTQOL SWITCH SPEED CONTEOL $C0/7C'Hf-0E HERO QOTQT/O/V INVENTOR.

QTTOZNEV Patented Mar. 2, 1954 UNITED STATES PATENT FFICE MACHINE TOOL OF THE DRILL PRESS TYPE HAVING MULTIPLE ROTARY TOOLS Fred G. Burg, Los Angeles, Calif.

Application June 10, 1948, Serial No. 32,198

19 Claims.

This invention relates to a machine tool, adapted to perform drilling, tapping or reaming operations, or analogous use. More particularly, it relates to a tool of this type in which a plurality of rotary tools may be used successively upon the work.

In many forms of work a number of operations including drilling, reaming or tapping must be performed. For example, a hole may be drilled, and then tapped or reamed; or else a number of holes of different sizes are to be drilled in the work. It is apparent, also, that the speed or" r0- tation of the tool must be selected to suit the work and the specific tool used.

In the common form of drill press, having a single tool, chuck or holder, such successive operations are time consuming, since the tool must be changed for each different operation; often the speed of operation must also be changed.

It is one of the objects of this invention to provide a machine tool that greatly facilitates such successive operations. More particularly, the invention makes it possible to bring a number of previously mounted rotary tools (drills, reamers, taps, etc.) successively into cooperative relation with the work, in an automatic manner.

In order to accomplish these results, a head is provided carrying a number of chucks or tool holders, each accommodating a specific rotary tool; only one of the tools however is in operating position and coupled to a source of rotary motion. The head can thenbe advanced toward the work to perform a drilling, reaming, or tapping operation. The act of urging the tool head toward its initial or starting position automatically causes adjustment of the head to place the next tool into operative position.

It is accordingly another object of this invention to provide a mechanism of this character.

It is still another object of thi invention to make it possible readily to predetermine independently the rates at which each of the tools is to be rotated.

It is still another object of this invention to make it possible to predetermine the limit of travel of the tool toward the work, whereby a definite depth of hole, or of the threads in a tap, may be obtained.

It is convenient to provide angular or rotary motion for the head that carries the tool. Movement of the head, occurring at the conclusion of each operation and withdrawal of the head, occurs always in the ame direction of rotation. In this way, any number of cycles of tool operations occur in natural sequence as the head is intermittently angularly adjusted.

It is accordingly still another object of this invention to provide a tool in which the multiple tool head is readily positionable for each operation in sequence, in a simple and efficient manner. This positioning operation may however be omitted, if desired, so that the same tool may be used in succession before a change is made.

It is still another object of this invention to ensure that the tool head will be rotated always at the same rate during the process of angular adjustment.

In order to make it possible to move the head angularly, the source of motion for the tools must be temporarily disconnected. The head is necessarily locked during the operation of the tool, against angular movement. It is accordingly another object of this invention to provide for unlocking the head and for unclutching the tool from the motor prior to angular adjustment of the head, and for subsequently locking the head and connecting the clutch.

It is still another object of this invention to perform these acts automatically upon retraction of the tool to a definite inactive position away from the work, and to ensure accurate registry of the head after it has been angularly adjusted.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of one embodiment of the invention. For this purpose there is shown a form in the drawings accompanying and forming part of the present specification. The form will now be described in detail illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of this invention is best defined by the appended claims.

Referring to the drawings:

Figure l is a front view of a drilling machine embodying the invention;

Fig. 2 is a side view thereof;

Fig. 3 is an enlarged sectional view, taken along a plane corresponding to line 3-3 of Fig. 1;

Fig. 4 is an enlarged detail section of a coupling member carried by the head structure;

Fig. 5 is an enlarged sectional view, taken along a plane corresponding to line 55 of Fig. 3;

Fig. 6 is a sectional view, taken along a plane corresponding to line 8-5 of Fig. 5;

Fig. 7 is a sectional view, taken along a plane corresponding to line 1-4 of Fig. 6;

Figs. 8, 9, and 10 are sectional views, taken along planes corresponding to lines 8--8, 9-9, and l0|0 ofFig.'7;

Fig. 11 is a pictorial view of one of the pins utilized in connection with the mechanism;

Fig. 12 is a pictorial view showing the ele-, ments that perform the clutching and unclutching of the mechanism for performing the operation of angularly adjusting the head of the machine.

Fig. 13 is an enlarged front view of the head structure, partly broken away;

Fig. 14 is a sectional view, taken along a plane corresponding to line l4l4 of Figs. and '7';

Fig. 15 is a view similar to Fig. 14, illustrating another stage in the operation of the mechanism;

Fig. 16 is a sectional view, taken along a plane corresponding to line [6-16 of Fig. 3;

Figs. 17 and 18 are fragmentary enlarged views of a part of the mechanism illustrated in Fig; 3;

Fig. 19 is a rear view of that portion of the apparatus illustrated in Figs. 17 and 18;

Fig. 20 is a sectional view, taken along a plane corresponding to line 26-20 of Fig. 3, and indicating the manner in which the head structure may be angularly adjusted;

Fig. 21 is a view similar to Fig. 20, but illustrating another phase of operation of the mechanism;-

Fig. 22; is an enlarged fragmentary view, partly in section, of the mechanism for angularly adjusting the head;

Fig. 23 is a top plan view of the machine;

Fi 24. is a fragmentary enlarged view, taken along a plane corresponding to line 24-24 of Fig- 1;

Fig. is a further enlarged sectional view of a portion of the apparatus shown in Fig. 24;

Fig. 26 is an enlarged sectional view, taken along a plane corresponding to line 26-25 of Fig. 24; and

Fig. 27 is a wiring diagram illustrating the control circuits for the apparatus.

As shown most clearly in Figs. 1 and 2, a standard I is provided carrying a work table 2. This work table 2 is provided with undercut slots 4- for facilitating the clamping of the work onto the horizontal surface 3 of the table 2. The work table 2 is furthermore vertically adiustab'le with respect to the standard I, as by the aid of dovetailed guides. Clamping devices 5 are provided for maintaining the work table or holder 2 in a definite position.

Supported above the standard I is a housing 8. that provides the main support for the drilling mechanism. This housing 5 is hollow, and is preferably formed as a casting. Its upper end projects outwardly to extend over the table 2.

A head structure 1 (see also Figs. 3, 13, 16, and 23) is supported by the aid of the housing 8. This head structure is angularly adjustable about the axis 8, which is in this instance horizontal and parallel to the surface 3 upon which the work is supported. This head structure is arranged to accommodate a series of rotary tools 220, such as taps, drills, reamers, or the like, which are equi-angularly spaced about the axis 8. The axes of these rotary tools extend radially of the axis 8.

In order that the head structure I may be angularl'y adjusted about the axis 8, it is rotatably supported upon a slide member 9 (Figs, 2, 3, and 23). This slide member, as will be explained hereinafter, is movable vertically toward and from the work table 2. This vertical movement causes the head structure 1 to move toward and from the work. Accordingly, angular adjustment of the head 1 about its axis 8 serves to bring a desired tool, having a vertical axis extending below axis 8, into operative relation with the work on the table 2. Vertical movement of slide member 9 toward the work in a downward direction, as viewed in Figs. 1 and 2, will cause an operation to be performed; and a movement upwardly of the slide member 9- will withdraw the tool from the work.

In order to form a guid for the slide member 9, use is made of a dovetail connection between it and the housing 5. As shown most clearly in Fig. 23, one vertical edge of the slide member 9 is formed with the tapered surface [0 cooperating with an adjustable gib II, which is accommodatedin a corresponding groove in the easing 6. The other edge of member 9 may b rectangular. The manner in which the slide member 9 is moved vertically, either toward or away from the work, will be described hereinafter.

The head structure 1 includes a circular casing [2 (Figs. 2, 3, 13, 23, 24, 25 and 26) which may be provided with a flang I3 at it righthand side. This casing l2, as shown most clearly in Figs. 3 and 13, is provided with a central boss l4 joined integrally with the right-hand wall of the casing, and is also provided with the ribs #5 extending transversely between the boss l4 and the cylindrical wall of the casing. This boss [4 is hollow and has an end wall Hi. This end wall 55 serves rigidly to support a shaft H, as by the aid of the screws [8. These screws engage a flange or collar formed integrally with the shaft ii.

The shaft [1 is rotatably supported in the hearing member 19 that is formed integrally with the slide member 9. I

A cover plate 20 is attached to the left-hand end of the casing I2 and is held against a shoulder 2 1' formed at that end of the casing.

The head structure 1 can, accordingly, be moved angularly about the axis 8 as required by the operation of the machine. It includes a plurality of rotatable shafts or spindles, shown most clearly in Fig. 13. In the present instance, six such shafts or spindles 22 are provided, the axes of whichv are radial to the axis 8 and fall in a common vertical plane. The ends of these spindles are provided. with threaded extensions 23 to which the chucks 24 or other tool holders may b attached.

The inner end of each spindles is supported in this instance by the aid of a. radial ball bearing structure 25 supported in an appropriate recess in the boss I4. Adjacent the outer end, the spindle is supported by the aid of a radial and thrust ball bearing structure 26 supported in the outer circular wall of the, casing 12. A collar 21, integral with. the spindle 22, forms an abutment for the inner race of the ball bearing structure 26. This collar may be flattened to accommodat a spanner Wrench when it is desired to install or remove a chuck 24. A bearing washer 26' may be appropriately fastened to the member l2 to maintain these hearings in place for each spindle.

Furthermore, each of the spindles 22 may be 7 designed for any particular purpose, and made a driving helical gear 3| having an axis of rotation parallel to axis 8.

There is a driving gear 3| associated with each of the spindles or shafts 22. As shown most clearly in Figs, 3, 4, and 13, the driving gear 3| is mounted on a shaft or spindle 32, as by being keyed thereto. The right-hand end of the shaft or spindle 32 is supported by the thrust ball hearing structure 33 mounted in the right-hand wall of the Casing l2. The left-hand end 34 of the shaft, which is of reduced diameter, is supported by the aid of the radial ball bearing structure 35 mounted in the cover plate 2|].

In order to space the gear 3| properly, use is made of a spacer sleeve 36 between the inner race of the ball bearing structure 33 and the right-hand side of the gear 3|. A nut 31 urges the gear 3| tightly in place. a

The right-hand end of each of the shafts or spindles 32 carries a detachable driven coupling member or clutch member 31. This coupling member is arranged in the space formed to the right of the boss I4, and comprises a number of engaging teeth 38 adapted to engage with corresponding teeth in a driving coupling member to be hereinafter described.

Referring to Figs. 3 and 13, it is seen that only that coupling member 31 is in engagement with the driving coupling member 39 which serves to drive the vertical spindle 32 that extends below axis 8, and in alignment with th vertical movement of the sliding member 9. The other coupling members (see also Fig. 16) are free of engagement with the driving coupling 39 and, accordingly, only the vertical spindle which is downwardly directed from the axis 8 is in operation. The driving coupling member 39 (Figs. 3, 5 and 6) is carried by the left-hand extension 49 of a driving shaft 4|. This coupling member 39 has an integral collar 42 which serves as a shift collar. This collar is splined, as by a key 43, to the extension 49 so that the coupling member 39 may be moved axially to couple and uncouple it with respect to the cooperating coupling member 31.

The shaft 4| is approximately rotatably supported by the aid of the thrust ball bearing structures 44 and 45. These ball bearing structures are mounted in the frame 46 that is attached to the slide member 9. This frame is also shown in Figs. '1 and 14. In order to fasten the frame 46 to the back of the slide 9, the slide 9 has a horizontal extension 46. overlying the vertical face of this extension is the flange 49 extending from the frame 46, and one or more bolts 50 serve to fasten the flange to the extension 48. Similarly, a bolt 41 passes through the ear 5| fastened to the frame 46. This bolt is threaded into the slide 9. A spacer sleeve 52 holds the ear 5| spaced from the back of the sliding member 9.

In order to drive the shaft 4|, use is made of a pair of bevel gears 53 and 54 (Fig. 6). Bevel gear 53 is keyed to the right-hand end of shaft 4|, and. the driving bevel gear 54 is similarly keyed to the lower extension 55 of a vertical shaft 56. The gear 54 is held to the extension 55 by the aid of the key 51 and a headless set screw 58 which passes through the hub of the gear 54. A thrust ball bearing structure 59 supports the lower end of the shaft 56. The inner race 60 of this ball bearing structure has an upper surface contacting with the shoulder 6| of the shaft 56.

Theouter race 63 of the ball bearing structure 59 is accommodated in a flange 64 formed on the frame 46. A cover plate 62 extends over thd ball bearing structure 59 and is fastened to the flange 64, as by a number of screws 65.

A cover plate 66 is similarly fastened to a flange 61 that extends obliquely beneath the gears 53 and 54. In order to hold the gear 53 in place, a washer 68 overlying the righthand face of the gear 53 is fastened on the right-hand extension 69 of shaft 4|.

'Rotary motion of shaft 56 is thus efiective to rotate the driving coupling member 39 and thereby that spindle 22 which extends vertically downwardly below the axis 8.

The shaft 56, as shown most clearly in Figs. 2, 3, and 23 is splined in a top collar ID. This collar 10 is rotatably supported in a thrust ball bearing structure I the outer race of which is disposed in a recess 12 in the upper end of the housing 6. Due to the splined connection between the shaft 56 and collar 16, this shaft 56 can move vertically while it is being driven by the aid of either pulley 13 or 14, both of which are integral with the collar 10. Accordingly, as the slide 9 moves up and down to move the head with respect to the work, the shaft 56 is corre-- spondingly moved.

The pulleys 13 and 14 are shown as having inclined belt engaging faces. A belt 15 is in engagement with one or the other of these pulleys. This belt is driven, as shown most clearly in Fig. 2, by the aid of one or the other of the pulleys 16 or 11 mounted on the shaft of an electric motor 18. This electric motor has a vertical axis, and its base is attached to a plate 19 mounted in the housing 6.

As will be explained hereinafter, this motor 18 can be driven at either of two speeds (high or low) in order that the proper speed may be selected for driving that spindle which is in cooperative relationship with the work.

Furthermore, the gear ratio of gears 28 and 3| can also be appropriately chosen for each spindle 32 to obtain a further choice in speed. As heretofore stated, gear 3| is rotated by the aid of the driving coupling member-39 and the driven coupling member 31.

Movement of the slide 9 in a vertical direction is effected manually by the aid of the rack and pinion mechanism shown most clearly in Figs. 1, 2, and 23.

Thus, mounted on the rear of the slide 9 is a rack 80. This rack 69 is in engagement with a pinion 8| mounted on a horizontal shaft 82 that is appropriately rotatably supported in bearings mounted on the housing 6. The shaft 32, as shown most clearly in Fig. 1, extends to the right of the machine and carries a collar 63. Radially extending from this collar 83 are a number of radial arms 84, any one of which may be grasped by the hand for rotating the shaft 82 and thereby raise and lower the slide 9. This slide 9, as heretofore stated, carries the head 1, as well as the frame 46. Accordingly, that spindle 22 which extends vertically below the axis 8 is moved to and from the work. r

A cover 85 may be supported in any appropriate manner over the slide 9 and the head structure This cover is cut away at the lower portion in order to expose the active spindle.

The arrangement is such that, when slide 9 is moved downwardly to perform a work operation, the head structure I is held against angular movement. However, when the slide 9 is urged upwardly when it is returned to its uppermost position away fromthe work, a mechanism is 7 aet nat qailr an m a-ed a adia t e osition at the e d angular-1y sheet he axis 11 and is b ine a Succeeding eR- nsll into ac iv re atio w th th Work As view d n Eia; th s steal r adies me t s ace ms isl-ie a. ceunter t oskw se direct on: a d), s tes her a e te holders cash dj s men made thrones an enele f de rees.

In order to ensure that the head structure l w l h cke fi m any s adiu ied 20 pes s m d at an. indexin pm show most learly ss 1. and .5-, R i ence ma also be had to Fig. 16. 4

Thus. he bac e the bead tr c ure o the e ss I2 i eriq w t s recesses $5. n each at es rece e eceammada ed a plus 8.1. of hard ma e ial in which there s a taper d rec ss t ee ed rec ss. i ada t d o b ena d by th t pered e d. 8 o an d xing p n 80- ind rins p n. 0 axi lly mevab e nv a b s r tand d see sol F st 1 nt gra w th the slid .1- The anner wh te the i k des e p n 8 s i drawn to e eositiqn. of Fi 15, and hat a lowed to return to engagin Post 9 il b ntensifi s described At the same time that the indeqging pin 9,0. is wi hdr wn to h nosi ie of iet. the dri ce r ie mem er .5 s e withd wn t or eas ment i the rir s eqndms; dr ven coupl n memb r .1. This. is accomp ished by the id o s if me hanis hown. meet clea y n s 5,, a d

hu t e riving c erlm m mile t ne se ya fil iii el .1.- h s shift fork. i mounted on an axial-lg moigable shaft, This shett s s own. nest e erlr F s;- and s able in ap ro riate; bea in stan a s 9! n 9.5.- nteer l wi h the castes 4.?- N mall a cemp ession' nr aeact te ars the snai toward the, le t. i 3- ta -sins en gement 0 5 th d i n o ineme nb e t9. with the r en pl n member ser es 3-6 as ts ghthan en ahuttins a wil termed a th hear n t nd r 5 its e l ed nd enseses a shoulder f rmed en. the sha t 9.3

The disengagement of the pin 91} and of the driv n cousins s attested iron. ur i of the slide m mhe t i urnerm st po tion- The lide a. a ompre ses ser es.- Eise- 1 and 23) serving as a resilient stop. Thisspring is supporte in IQQQSF ill tifl P. I}? llfill m abut-arm 2% t at i c rried by a nes 2.2. This post 22-5 is asten d 329 he we r me-.6 N v he al for e exer e oil-shaft. o

moving slide membe 9.- urwe dlr s nsutfisien t cause the autqm t answer enl s ment- Howevei'. when it is dfi il d diill li Elhead a greater-force is used on shaft, 82 an dth espsing .9. is ompressed som wha fur her: the sli e 9 will then be in suchposition as to initiate the adjustment.

When this. uppe m st pos tie s. r ached. a control shaftdl (Figs. 6, 7-,, l4, and 1 5) iscaused to rotate through a cy le. i ins ance, a counter-clockwise direction) and throirgh a cornplete revolution. as. vi w d n Elias. l4; and 15. This. shatt s1, asv shown most clearhe 6, 7, l4, and 15, is. jonr-nalled at its. right-hand end, as viewedin Fig. 7., in a wallet the casin 4.6..and is similarly journalled at its left hand end in anopposite wall ofthis casing.

Theshaft 91 carries a multiple cam structare 98.. This cam structure 98;, is keyed to. the Shaft k. In the. quie sent msia ion iii atllitiillzi of h se cam, e emen s i o erative. However. immediately upon a small angular movement in, 8., connter clockwise direction, cam 99 momentarily causes disengagement of the indexing pin from one of the tapered holes 88 in plug 8 1. In order t effect this, a'lever llll is util Zed having an upright arm eng ing a ski I02 n n ex ng pin 91]. The lever ID! is pivotally mounted on a pin 13, fixed to a wall of the casing 45. When this arm is rotated in a clockwise direction about the pin I03, the indexing pin 91! is withdrawn, as illustrated in Fig. 15. A tension spring 104 (Fig. 14) serves to urge the pin 9 0 into indexing position.

The movement of the lever arm I!!! to the re leasing position of Fig. 15 is effected by the cam 9.9 This 2a a es e a m n th path of the cam 99. Shortly after the cam 99 effects withdrawal of the pin $10, the head Stru ture 1 is rotated about its axis 8 in a manner to be hereinafter described. This permits the spring 104 to urge the pin 90 into contact with the left-hand face of the casing 12 so that the pin 90 can enter into the next tapered aperture 88 as soon as the drum structure 1 has completed its angular movement.

Similarly, cam H18 operates to shift the driving coupling member 39 to the right, as viewed in Figs. 5 and 6. This causesv disengagement of the drive from that spindle 22, which projects vertically downwardly below axis 8 For this purpose the shift fork shaft 93 is provided with a slot I68. In this slot the end I01 of an arm I08 projects. This arm N18 is mounted on a pin I09 supporte n the frame 46. It has a surface H0 which is vertical in the quiescent position of Fig. i l and which is in the. path of movement of the cam Int. As this cam moves in a counter-clockwise direction, the shift fork 91 is moved toward the right to the position of Fig. 15 by engagement of the cam I89, with the arm [08. The cam [Dd is active for a considerable angular extent so as to retain the drivin coupling member 39 in disengaged position until after the head structure i has been rotated to its new position.

A s m nt at he ad s ruc r 1 lso effe ed y r ati n f he, af 91- Thu t i shaft 9 l-, as shown most clearly in l 'igs, 3, 5., and 7, carrie a drining helical ear H1 at itsv lefthand end, as viewedin '7. Ifhis gear serves to drive a ea "2 ng, a ra lel, wit the axis 8 and that is keyed to. a' shaft [13.- Thi shaft 1 5 a pr riate y suppo ted o r ta n n bear n st ndards. 1 (F g, l a p iat mee ted pmth fr me .6-

The sha t H s a so indica ed. ig 0. 21 and 2.2- t carr e a s l f nd nd a di at rotat s n a c ckwise direc i n. v e d from the ba k r tnehead s ru u e Th d c 1 i carri sa. ank in i it. i e ed en is cra pinisan wi mem er- HE h s; wl memb 1 is y e ade of a oli b r f mat r l. wi h. n arcuate roo e H1 t i -ha d e e- E tending across this s a at he 1129 en s a pin H8. and freely rotatable; e pnt th s is h slot li'l: isa pawl roller He. roller H9, as shown most clearly in Fiss. 2. and 2. i ntended to engage any one. of the series of circular recesses. t: formed in he P r shero a ratc e wheel'lZ-t.

Rat het Z firml fix dn t e shaft H o W e. h ed; mat e i a c There are as many recesses I20 as there are tool h lders, and equ l-. 54 eat d abou the. 8, In he srese t. stance t er a en in o x y degrees between each of the recesses I20 so that, by rotation of the crank disc II4 through one revolution, the ratchet wheel I2I can be advanced by one-sixth of a revolution. The slot I I! serves to accommodate the left-hand portion of the ratchet wheel I2I, as shown most clearly in Fig. 21. A washer 223 (Fig. 3) is interposed between the ratchet wheel I2I and the back wall of slide 3, whereby axial movement of shaft II is restricted.

Each of the recesses I20 is so arranged that it has an overhanging portion or tooth I22 which serves as an abutment against which the roller II9 can be urged as the crank shaft II3 rotates.

In the quiescent position shown by the full lines of Fig. 20, th pawl roller H3 rests against the outer circular periphery of the ratchet wheel I2 I. The pawl H is urged against the ratchet wheel I2I by any appropriate resilient means. In the present instance a yoke I22 extends around a collar I23 joined to the reduced extremity of shaft II. Each end of the yoke serves as an anchor respectively for springs I24 and I25. .These two springs are formed of a single piece of wire bent around a pin I25 that projects to the right of the pawl H5, as viewed in Fig. 22 and is supported thereby. This pin is supported appropriately near the upper edge of the pawl I I5.

In the quiescent position indicated by the full lines of Fig. 20, the crank pin H5 is on an axis slightly below the horizontal line passing through the axis of shaft II3. Accordingly, when the crank disc II4 begins its rotation in a clockwise direction, the pin H5 is moved downwardly to move the pawl roller H9 into engagement with one of the recesses I20. As soon as the pin II5 has moved to a position corresponding to the dotand-dash position of Fig. 20, the roller H3 is in engagement with the upper wall of a recess I20. Continued rotation then causes the pawl II6 to move the ratchet wheel in a clockwise direction. The full line position of Fig. 21 illustrates the completion of the rotary movement of the ratchet wheel I2I.

Further clockwise movement of the crank disc I It causes a disengagement of the pawl I It. This occurs by the aid of a cam member I2! attached to the shaft II. In this instance the cam member I21 is in the form of ahexagon. The corners of the hexagon operate as cams to en age the side of the pawl IIt. In this way the point of contact I28 serves as a fulcrum about which the pawl H5 is swung as the crank pin I I5 moves in a clockwise direction, as viewed in Fig. 21. By the time the crank pin II5 reaches the position indicated in the dot-and-dash lines, the pawl H3 has been swung completely out of the recess I20. I

The swinging of the pawl IIG out of engagement occurs atthe end of the stroke, and is facilitated by theprovision of the plane surfaces I29 on ratchet wheel I2 I-, that reach transversely from the left-hand edge of the recess I20 to the periphery of the ratchet wheel I2I. 1

The ratchet wheel I 2| is moved for each revolution of the crank disc-H4 through an angle of sixty degrees. A slight deviation from this angle does not affect the accurate registry of the head structure I with relation to the axis 8 of the head. Accurate registry is performed by the aid of the indexing pin 30, shown in Figs. 14 and15.

Once the head "structure I starts to move to a succeeding angular position, the cam 99 (Figs. 14 and 15) passes beyond the army I05 and the spring I04 urges th indexing pin 00 against the right-hand surface of the casing I2. Accordingly, upon completion of the angular movement of the head structure 1, the indexing pin is urged by spring I04 into the substantially aligned recess 88 and, if necessary, gives the head structure I a slight angular movement to align the head structure accurately.

Often tools 220 must penetrate the work only to a required depth. Means the provided to ensure that the advance of the tool to the work is limited. The amount of advance is adjustable. Furthermore, the depth reached by each tool is also independently set.

This is accomplished by the aid of apparatus illustrated most clearly in Figs. 3, 5, 22, and 23.

The slide member 9, as shown in Figs. 3 and 23, has a horizontal flange I30 at its upper end. Rotatably mounted in an aperture I3I in this flange is a collar structure I32 having an upper flange I33 and a lower flange I34 that engages the upper and lower surfaces of the flange I30. The lower flange I34 can be detachable to facilitate assembly.

The collar I32 carries six headless adjustable screws I35 equi-distantly spaced about the axis of the collar structure I32. Each of these screws can be independently adjusted to vary the distance between the bottom of the screw and a projection I36 formed on the housing 6. This projection I33 is in the path of movement of one of the screws I35 as the slide moves downwardly. Contact of the lower end of one of the screws with the projection I36 limits the downward movement of the slide member 3.

As shown most clearly in Fig. 23, only the extreme right-hand screw I35 is in a position to be stopped by the projection I36. However, a succession of angular movements of sixty degrees of the collar I 32 servesv to position successive screws I35 above the projection I36.

Each of the screws I35 corresponds to a depth to be attained by a corresponding tool that has its axis below the axis 8.

The collar I 32 is automatically adjustable simultaneously with the adjustment of the head structure I. For this purpose the collar I32 is mounted on a long shaft I3I. This shaft is provided with a bearing sleeve I38 (Fig. 22) formed in an arm I39. This arm I39 is shown as integral with the slide 9.

The lower end of the shaft I31 carries a helical gear I40 that meshes with a corresponding helical gear I4I mounted on the shaft II, these gears I40 and MI having a one-to-one ratio. Accordingly, the angular movement of collar I32 is made equal to the angular movement of shaft I1.

For each position of the head structure I there is a corresponding screw I35 operatively associated with the projection I 36.

As heretofore stated, the operation of withdrawing the indexing pin 90 and the drivingcoupling member 39, and subsequent rotation of the head structure I is accomplished by rotating the annular groove I44. This collar carries one portion of a clutching mechanism for coupling the shaft 91 to a continuously rotated worm wheel I45. .This worm wheel I45 is freely rotatable with respect to shaft 91, and is driven by a worm 6.

This worm I46 is splined to the shaft M, as shown most clearly in Fig. 6. Accordingly, it

. derives its motion from shafts 56 and M that are continuously rotated by the electric motor 18.

l The worm I46 is held in proper relation with the worm wheel I45 by the aid of the spacer collars I41 and I48.

While the clutching elements are inactive, the worm wheel I45 merely rotates freely on the shaft 91 which is held against rotation. A stop for positively holding the shaft against rotation is shown most clearly in Fig. 8, which shows a pin I48 (see, also Fig. 11). This pin I49 carries at its upper end an inclined tooth I50. The vertical face of this tooth I50 engages a shoulder II formed in a notch in the collar I42. The pin I49 is guided in the frame 46 for longitudinal movement, and is urged to engaging position by the aid of a compression spring I5I' (Fig. 7). This compression spring abuts the lower end of the pin I40. A spring retaining projection I52 is provided at the bottom of the pin I46. The

spring is held in place by the headless screw I53 threaded into a portion of the frame 46.

The clutch element carried by the collar I42 is in the form of a longitudinally movable key I54. This key, as shown most clearly in Fig. 8,

has an axis of movement parallel with the axis of shaft 91. It is urged toward the right, as viewed in Fig. 7, toward engaging position by the aid of a compression spring I55. This spring I55 is appropriately located in a recess I56 (Fig.

7 12) formed in the key I54.

The other element of the clutch comprises a plate I51 (Figs. 7 and that is held to the leftmoved in succession past the key I54. So long I as the key 154 is held in the restrained position of Fig. 7, no motion is transmitted from the wheel I 45 to the collar I42 and shaft 91.

The key I54 is restrained against clutching movement by the aid of a pin I60 parallel to pin I49. This pin I60 is shown most clearly in Figs. 7, 9, and 12. It is guided in the frame 46 and urged ,upwardly by a compression spring I6I,

similar in construction to the compression spring The upper end of pin I60 forms a projection I62. This projection I62 has a slanting face I63 oblique to the direction of movement of key I54.

It cooperates with a corresponding oblique surface I64 forming one shoulder of a slot I65 in the bottom of key I54, in a manner to be hereinafter described. This slot I65 has an inner portion formed with parallel sides into which the projection I62 fits for restraining the key I54 in inactive position.

Withdrawal of the pin I60 permits the spring I55 to urge the key I54 into one of the recesses I59, and coupling is eifeoted between the shaft 81 and wheel I45.

As shown most clearly in Figs. '7 and 9, the

aevdee 12 projection I62 of the pin 60 is accommodated in the groove I44. In this way, as soon asthe pin I60 is pulled downwardly against the force of spring I6I, the projection I62 is removed from slot I65. Subsequently the pin I60 is released, and the projection I62 then rides on the bottom of groove I44, until unclutching is again effected.

Both pins I49 and I60 are simultaneously withdrawn when the shaft 91 is to be rotated to perform the adjusting functions heretofore described. Shortly after these pins are withdrawn, the pins are allowed to move back into stopping position. The tooth I50 of pin I46 then rides on the periphery of the collar I42; and, when the collar has made a complete revolution, the tooth is effective accurately to restrain rotation beyond one revolution. At the same time, key I 54, being advanced to the right to clutching position, has its oblique surface I64 in the path of oblique face I63 of pin projection I62, and these two surfaces coact to urge the key I54 to disengaging position. This disengagement thus stops the rotation of shaft 91 after a complete revolution. A slight further rotation brings the projection $62 into the parallel sided portion of slot I65. The shaft is definitely stopped after an exact revolution by the engagement of tooth I50 with shoulder I51.

To begin the cycle, the pins I46 and I60 are momentarily withdrawn as the slide member 5 is urged to its uppermost position against the stop spring 9'. For this purpose, both the pins 46 and I60 are connected to a lever I66 pivoted on a pin I61. This pin I61 is appropriately supported on the frame 46. The lever is coupled to the pin I49 by the aid of a cross pin I68 (Figs. 7, 8, and 9). The left-hand end of the pin engages the slot I69 in pin I49. It also engages a slot I60 in pin [60. Accordingly, as the arm I66 is moved in a clockwise direction, as viewed in Fig. 9, both pins I49 and I60 will be retracted and the adjusting mechanism is operated.

In order momentarily to depress the arm I66 to the desired dot-and-dash position of Fig. 8, use is made of an abutment I I0. This abutment I10 is in the path of the right-hand end of the arm I66 as the slide 9 is urged to its uppermost position.

As shown most clearly in Figs. 3, 1'7, 18, and 19, the abutment I10 is in the form of an arm that is pivoted on a pin I" which is stationary with respect to the apparatus. Thus, the pin IN is mounted on a bracket I12 which is attached to a stub shaft or rod I13. This stub shaft I13 is attached at its left-hand end, as shown in Fig. 19, to a wall I14 of the main housing 6. The shaft or rod I13 passes through the bracket I12, and a set screw I15 is provided to hold the bracket firmly on the rod I13. Compression spring I16, accommodated in a recess in the bracket I12, urges the abutment arm I10 toward engaging position.

Accordingly, when the slide member 9 moves upwardly, the right-hand end of the arm I66 contacts the end of the abutment arm I10. Further upward movement of the slide 0, compressing spring 9', is effective to withdraw the pins I40 and I60, since the arm I 66 is held against further movement by the abutment arm I10.

It is, however, desirable to release arm I66 shortly after the adjustment mechanisms are actuated and thereby to cause the pins I49- and I60 to be urged into operative relationwith'the collar I42.

For this purpose, the shaft I I 3 which rotates the tool that is in operative position.

the head structure 1.

the crank disc II4 (Fig. 5) has, at its right-hand end, a resetting arm I11, shown most clearly in Figs. 17, 18, and 19. In the inactive position, this reset arm is vertical, as shown in Fig. 19. However, after shaft II3 has moved through about ninety degrees, corresponding to the beginning of the movement of the crank disc I I4, this arm approaches the horizontal position indicated in the dot-and-dash lines of Fig. 19. The arm contacts a roller I18 mounted on the abutment arm I10. It moves the roller, accordingly, toward the right, as viewed in Fig. 18, and releases the arm I66 from the abutment I10. Accordingly, the clutch control pin I60, as Well as the indexing pin I49, are released and are in proper position to stop the rotation of shaft 91 after it has made one complete revolution.

Accordingly, as soon as the slide member 9 is in its uppermost position, the controlling acts performed by shaft 91 occur in proper sequence to release the head structure 1, to withdraw the driving coupling member 39, and to operate the pawl and ratchet mechanism for angularly adjusting the head. Upon conclusion of this adjustment, the shaft 91 is stopped. Then the slide member 9 may be moved downwardly 'by the hand mechanism 82, 83, and 84 to operate on'the work. Upon conclusion of the operation, the slide member 9 can again be moved upwardly, and a new adjustment of the head structure 1 is effected to bring the tools successively into operative position.

The electric motor 18, shown in Fig. 2, has control circuits such that its speed may be adjusted to conform with the requirements of the tool that is in operative position. This is shown diagrammatically in Fig. 27. In this figure the incoming mains I19v serve to supply power to the motor 18 through a control mechanism indicated diagrammatically by the rectangle I80. The main switch I8I serves to deenergize the system as required. A small switch mechanism I82 is indicated in the diagram of Fig. 2'7 for controlling the speed of the motor between a high and low speed. This may be in the form of a microswitch. It serves to control the speed of When the switch I82 is open, the motor 18 may have a high speed of rotation; and, when it is closed, it may have a low speed of rotation.

The switch I82 is arranged to be automatically controlled by a cam arrangement mounted on Thus, as shown most clearly in Fig. 24, this switch mechanism I82 (Figs. 23 and 24) is shown as mounted on the main housing 8. A cover I83 in Fig. 23 extends over the switch.

The switch I82 is arranged to be operated by the aid of a lever I84 pivoted in ears I85 extending along the side of the casing 8. The righthand end of the lever is arranged to depress the spring arm I88 that operates the switch I82 when the lever I84 is rotated about its pivot formed by a pin I81. A leaf spring I88 urges the arm I84 outwardly with respect to the switch I82 so as to leave the switch in one of its two controlling positions.

The left-hand end of the arm I84, as shown in Fig. 24, carries a cam follower roller I89. This cam follower roller is arranged to be actuated by a cam I90 mounted radially of the axis 8 and carried by the casing I2 of head 1. There are as many of the cams I90 as there are spindles 22. They are, furthermore, so positioned that one of the cam followers I90 may be placed in active position with the arm I88 when the head structure 1 is in any one of its adjusted positions. The switch station in Fig. 13 corresponds to the right-hand side of the drum structure I. Accordingly, that particular cam I99 which is in active position with respect to the arm I84 determines the speed of the motor 18, driving the active spindle 22.

Each of the cam structures I90 can be either placed into or out of cooperative position with respect to the roller I89. In this way, the switch I82 is either actuated or left unactuated, corresponding to the two speeds of motor 18.

For aligning the cam I90 in either active or inactive position, the cam is mounted on a slide plate I9I (Figs. 25 and 26). This slide plate can be urged in a direction parallel with the axis 8 by the aid of a knob I92. This knob has a narrow neck I93 passing between the flanges I94 and I95 of the'guide for the slide I90. In the full line position of Fig. 25, the cam I90 is is in switch operating position. In the dot-and dash position, the cam I90 has been moved toward the left and out of cooperative relationship with the cam roller I89.

In order to retain the slide I9I in either of its two positions, a ball restraint mechanism is used and is illustrated in Fig. 25. Thus, the slide I8I is provided with a pair of spaced concavities I98 and I91 capable of receiving the ball restraint I98. This ball restraint is. accommodated in a recess I99 in the casing I2. A compression spring 200 in the recess urges the ball into engagement with either of the two recesses I96 and I91.

As the head structure 1 is adjusted to any one of its angular positions in succession, a different cam member I90 may be brought into operative position with respect to the arm I84. Accordingly, the speed of the active spindle can be thereby determined. For each position of the head structure 1, there is a cam which comes into play for determining this speed.

In order to make the speed of adjustment act at the desired rate, the arrangement is such that the motor 19 is adjusted just prior to the time when the head 1 is rotated. For this purpose, another switch mechanism 20I (Figs. 3 and 2'7) is provided which is actuated when the slide member 9 returns to its extreme upper position.

This switch member is operated by an arm 202 attached to the cover member 82. As the cover member moves up with the slide member 9, it contacts the operating arm 203 and causes the speed of the motor to be adjusted to a desired value.

A start button 239 and a stop button 23I may be appropriately supported on standard I, and

are shown in Fig. 2'7.

lhe adjustment of head 1 is preferably performed at a relatively fast rate of the order of one second. When the motor 18 is operating on the larger pul1ey13, the switch mechanism 201 merely causes the motor to operate at high speed. However, when the motor drives the smaller pulley 14, the speed of adjustment would be too great. Accordingly, a manually operated switch 232 mounted on head 6 may be used to condia low speed when the larger pulley I3 is active. This switch 28I may thus be operated to control the speed of adjustment.

The modeof operation of the mechanism may be briefly summarized. During normal-operation the coupling member 39 is in driving relation with the coupling member 31 that drives a spindle 22 (Figs. 3 and 13). On'the completion of the drilling or reaming operation, the slide member 9 is moved upwardly. In moving upwardly the arm I" is contacted by the arm I66, and the switch MN is also operated. The speed of the motor is thereby increased at the same time the shaft .81 (Fig. '7) is clutched to the wheel 145 that is continuously driven. This shaft 91 makes one complete revolution and then stops. The cams :99 and 100 (Figs. 14 and 15) are actuated promptly upon motion of shaft 91, to release the indexing pin 91! and to withdraw coupling member 39.. The crank disc H4 is also operated by the motion of shaft 91 through the shaft 113, and the head is adjusted to a sucseeding position by the ratchet mechanism shown in Figs. 20, 21, and Y22. The cam I subsequently returns to inactive position and the coupling 39 is then moved into driving engagement with the corresponding coupling 31. At the same time, the indexing pin 96 snaps into position in one of the recesses 88 in the head casing I2. succeeding tool operation can now be performed.

As soon as head structure 1 assumes a new adjusted position, the switch I82 is controlled in such a way as to choose the proper speed of operation for the active spindle. The speed of the spindle can also be varied, as heretofore stated, byv appropriate choice of the ratio of the drive gears 28 and 31 The one-revolution clutch structure and its trip mechanism, as illustrated. in Figs. 7 to 11,

inclusive, are made the subject matter of an application filed on March 14, 1952, in the name of Fred G. Burg, Ser. No. 276,622, and entitled Cyclically Operable Power Transmission Mechanism.

The speed control system exemplified by the structure illustrated in 23, 24, 25, and 26 is described and claimed in an application Ser. No. 276,755, filed March 15, 1952, under the name of Fred G. Burg, and entitled Speed Control System for Machine Tools.

The inventor claims:

1. In a machine tool adapted to perform operations on work by the aid of rotary tools: an

angularly adjustable head having a plurality ofa'v angularly spaced tool holders about the axis of the head; said axis being normal to the axes of the tool holders; means restraining said head along the axis of said rotation; coupling members respectively associated with each tool holders".

for driving it; driving means having a coupling member positioned for engagement with that one of the tool holder coupling members that has its axis aligned with the driving coupling member; means for moving the head toward and from thework; and-means responsive to the move- 'ment of the head'away from the work toward an initial position for disengaging the driving coupling member, then angularly adjusting the head about its axis to position a succeeding toolatively movable as the head is brought toward and'from the work; and means movable with the head, and contacting said abutment when the head is moved from the work to an initial position, to render said restraint inefiective.

2. In a machine tool adapted to perform operations on work by the aid of rotary tools: an angularly adjustable head having a plurality of anguiarly spaced tool holders about the axis of the head; coupling members respectively associated with each tool holder for driving it; driving means having a coupling member positioned for engagement with one of the tool holders coupling members that has its axis aligned with the driving coupling member; means for moving the head toward and from the work; mechanism for angularly moving the head; mechanism for disengaging the driving coupling member; said mechanisms being inactive during operation of the tool on the work; .a transmission having a continuously rotating shaft for operating said mechanisms; a trip mechanism operated by the movement of the head away from the work toward an initial position and power means energized by said trip mechanism for imparting a unit of angular motion from said shaft to said mechanisms; said trip mechanism comprising a restraint normally maintaining said actuator mechanism inactive; an abutment with which the head is relatively movable as the head is brought toward and from the Work; and means movable with the head, and contacting said abutment when the head is moved from the work to an initial position, to render said restraint inefi'ective.

3. In a machine tool adapted to perform operations on work by the aid of rotary tools: an angularly adjustable head having a plurality of angular-1y spaced tool holders about the axis of the head; coupling members respectively associated with each tool holder for driving it; said coupling members being carried by the head; driving means having a coupling member movable with respect to the head and positioned for engagement with that one of the tool holder coupling members that has its axis aligned with the driving coupling member; means for movingv the head toward and from the work; a trip mechanism operated by the movement of the head away from the work toward an initial position; power means energized by said trip mechanism for disengaging the driving coupling member, then angularly adjusting the head about its axis to position a succeeding tool holder into operative relation to the work and the driving means, and then reengaging said driving coupling memher; a spring-pressed pin indexing the head and locking the head against adjustment; and means operating in synchronism with the adjusting means for moving the pin out of locking position and then releasing the pin to permit it to relock the head on conclusion of the adjusting operation; said trip mechanism comprising a restraint normally maintaining said. actuator mechanism inactive; an abutment with which the head is relatively movable as the head is brought toward and from the work; and means movable with the head, and contacting said abutment when the head is moved from the work to an initial positionfto render said restrain ineffective.

4. In a machine tool adapted to perform operations on work by the aid of rotary tools: a head having a plurality of spaced tool holders and adjustable to bring a selected tool into operative relation to the work; means for moving the head toward and from the work; a driving mechanism for the selected tool; a coupling means carried by each tool holder for the driving mechanism; a cooperating coupling means carried by the driving mechanism and serving to connect the selected tool and the driving mechanism; a cam for moving the driving coupling member out of engagement with the tool holder coupling member; a driver for the cam; a clutch means urged to engagement for coupling the cam driver to the cam; means holding the clutch means out of engagement; means responsive to the return of the head toward an initial position away from the work for moving the holding means so as to permit the clutching means to engage; and means operated by movement of the cam for conditioning said holding means to render it effective to disengage the clutch upon predetermined angular movement of the cam.

5. In a machine tool adapted to perform operations on work by the aid of rotary tools: a head having a plurality of spaced tool holders and adjustable to bring a selected tool into operative relation to the work; means for moving the head toward and from the work; a driving mechanism for the selected tool; a coupling means carried by each tool holder for the driving mechanism; a cooperating coupling means carried by the driving mechanism and serving to connect the selected tool and the driving mechanism; a mechanism capable of performing repeated cycles for intermittently adjusting the head; a cam for moving the driving coupling member out of engagement with the tool holder coupling member; a driver for the cam and for the head adjusting means;

a clutch means urged to engagement for coupling the cam driver to the cam; means holding the clutch means out of engagement; means responsive to the return of the head to an initial position away from the work for moving the holding means for permitting the clutching means to engage; and means operated by movement of the driver for conditioning said holding means to render it effective to disengage the clutch upon predetermined angular movement of the driver.

6. In a machine tool adapted to perform operations on work by the aid of rotary tools: a head adjustable about an axis and having a plurality of tool holders having axes radial to the axis of the head, said tool holders being uniformly axially spaced; means forming a guide for the head to permit the head to move toward and from the work in a direction transverse to the head axis; one of the tool axes being aligned with the direction of movement of the head with respect to its guide; means for moving the head with respect to the guide; a drive mechanism movable with the head for operating atool holder the axis of which holder is aligned with the, movement of the head with respect to its guide; means movable along with the head with respect to its guide for unclutching the drive mechanism; means movable along with the-head for angularly adjusting the head about its axis by uniform increments corresponding to the angular spacing of the tool holder axes; a;transmission for operating both the unclutching means and angular adjusting means; said transmission having an axis about which at leasta portion of the transmission is rotatable; and means responsive to movement of the headaway from the work toward an initial position for connecting the transmission mechanism to the unclutching means and the angular adjusting means through a cycle to bringa succeeding tool holder into operative position with respect to the work and to cause reengagement of the clutching means after the head is angularly adjusted, comprising a restraint normally maintaining said transmission mechanism inactive; an abutment with which the head is relatively movable as the head is brought toward and from the work; and means movable with the head, and contacting the said abutment when the head is moved from the work to an initial position, to render said restraint ineffective.

'7. In a machine tool adapted to perform operations on work by the aid of rotary tools: a head adjustable about an axis and having a plurality of tool holders having axes radial to the axis of the head, said tool holders being uniformly axially spaced; means forming a guide for the head to permit the head to move toward and from the work in a direction transverse to the head axis; one of the tool axes being aligned with the direction of movement of the head with respect to its guide; means for moving the head with respect to the guide; a drive mechanism movable with the head for operating a tool holder the axis of which holder is aligned with the movement of the head with respect to its guide; means movable along with the head with respect to its guide for unclutching the drive mechanism; means movable along with the head for angularly adjusting the head about its axis by uniform increments corresponding to the angular spacing of the tool holder axes; a transmission for operating both the unclutching means and angular adjusting means; said transmission having an axis about which at least a portion of the transmission is rotatable; and means responsive to movement of the head away from the work toward an initial position for connecting the transmission mechanism to the unclutching means and the angular adjusting means through a cycle to bring a succeeding tool holder into operative position with respect to the work and to cause reengagement of the clutching means after the head is angularly adjusted; comprising a key longitudinally movable in a direction parallel to the axis of transmission for rendering the transmission effective; said key when active to render the transmission effective, being rotated about the transmission axis, and not rotated when the key is inactive; a dog restraining said key, said dog having a surface inclined to the transmission axis, and the key having a correspondingly inclined surface connecting with a surface normal to the transmission axis; resilient means urging said dog toward engaging position of the key and the dog; means toward which the head moves when it is being retracted from the work, for causing the dog to recede from the key; and for rendering the transmission effective; and means effective upon initiation of the drive of the angular adjusting means and the unclutching means for releasing the dog, said inclined surfaces being thus effective after a cycle to withdraw the key to disconnect the clutch.

8. In a machine tool adapted to perform operations onrwork by the aid of rotary tools: a head adjustable about an axis and having a plurality of tool holders having axes radial to the axis of the head, said tool holders being uniformly axially spaced; means forming a guide for the head to permit the head to move toward and from the work in a direction transverse to the head axis; one of the tool axes being aligned with the direction of movement of smog-3e the head with respect to its guide; means for moving the head with respect to the guide; a drive mechanism movable with the head for operating a tool holder the axis of which holder is aligned with the movement of the head with respect to its guide; means movable along with the head with respect to its guide forunclutchthe drive mechanism; means movable along with the head for angularly adjusting the head about its axis by uniform increments corresponding to the angular spacing of the tool holder axes; a transmission for operating both the unclutching means and angular adjusting means; said transmission having an axis about whichat least a portion of the transmission is rotatable; and means responsive to movement of the head away from the work toward an initial position for connecting the transmission mechanism to the unclutching means" and"the angular adjusting means through a cycle to bring a succeeding tool holder into operative position with respect to the work and to cause reengagement of the clutching means after the head is angularly adjusted; comprising a key longitudinally vmovable in a direction parallel to thaxis of transmission for rendering the transmission eiiective; said key when active to render the transmission effective, being rotated about-the transmission axis, and not rotated when the key is inactive; a dog restraining said key, said dog and key having surfaces inclined to the transmission axis; resilient means urging said dog toward engaging position; means toward which the head moves when it is bein retracted from the work, for causing the dog to recede from the key, and for rendering the transmission effective; means effective upon initiation of the drive of the angular adjusting means and the unclutching means for releasing dog, said inclined surfaces being thus effective after a cycle to withdraw the key; and means operative with the dog for ensuring that the cycle during which the transmission is effective terminates at a precise point of moveme nt of the angular adjusting means and the unclutching means.

9. 11;, machine tool adapted to perforinoperntes on work by the aid of rotary tools: an adjus ablehead having a plurality df spaced tool holders a source of motion for driving the tools; means forming a detachable coupling-from the source ofmotion to a selected tool homes; a power driven transmission mechanism vfor adjusting the head and including a clutch having separable parts; nieans restraining one of said parts; means for moving the head toward and from the'work; ineans responsive to movement of the head away from the work toward an initial position for removing said restraining means; and means responsive to the initiation of the adjustment ior moving the restraining means to position in which the clutch parts are caused to be separated upon a definite extent of movement of the transmission.

10. In a machine tool adapted to perform operations on work by the aid of rotary tools: an adjustable head having a plurality of spaced tool holders; a source of motion for driving the tools; means forming a detachable'cou pling from the sourceof motion to a selected'tool holder; a power driven transmission mechanism for adjusting-the head and including a clutch having separable parts; means controlling one of the clutch parts and movable between a position in which said clutch "part is restrained against clutching engagementand another position permitting the clutch part to move into engagement; movable stop means for precisely limiting the extent of movement of the transmission mechanism; means for moving the headtoward and from the work: means responsive to movement of the head away from the work toward an initial position for moving the control means out of restraining position and for moving the stop means to free the transmission; and means responsive to the initiation of the adjustment for moving the means responsive to movement of the head toineiiective position to release the controlling means and the stop means so that they may become elfective upon completion of the adjustment to unclutch the clutch'and to limit the adjustment.

11. In a machine tool adapted to perform operations on work by the aid of rotary tools: an adjustable head having a plurality of spacedtool holders; 9, source of motion for driving the tools; means forming a detachable coupling from the source of motion to a selected tool holder; a transmission mechanism for adjusting the head and including a clutch having separable parts; one of said parts being slidable into and out of engageme'nt with the other part, and being nonrotating when the clutch parts are disengaged, and rotating with the transmission when the clutch parts are engaged; means resiliently urging said one of the parts toward engaging position; means movable transversely of the said part for restraining movement of said part; means urging said restraining means to restraining position; "means for moving the head toward and from the work; means responsive to the movement of the head away from the work toward an initial position for overcoming said urging means to free the clutch part; andmeans'responsive to the initiation of the adjustment for releasing said urging means; 'said transversely movable partand the clutch part having cooperating surfaces to cau'sethe clutch part to be moved out of clutching engagement when the transmission-has moved through a definite angle.

12. In a machine tool adapted to performoperations on workby the-aid of rotary tool-Bran adjustable head having a plurality of spaced tool holders; a source of motion for driving the tools; meansformihg'a detachable 'coupling from the source'of motion to a selected tool holder; a transmission mechanism for adjusting the head and including-a clutchhavin'g separable partsj one of said parts being a bolt movable in a direction parallel "to -the axis "of the clutch and non-rotary until it engages the other'part-of the-clutch: a spring urging said bol-t toward engaging position; means movable relative to-the bolt in a direction radial of the axis of the clutch ior holding the boltbut ojf engagement; a second spring for urging the said holding means towardholding position; means for causing movement of the'holding mean away from the holding position and againstthforce of said second springe and means releasing said movement causing means; said bolt and th'e' holding means 'havingeooperatingsurfacssuchthat when the-bolt approaches its beginning 1 position after the clutchparts are in engagement, said bolt is retracted by the holding means to-disengaged position.

13. in a machine toobadapted to perform operations onworkbytheaid of rotary tools: an' ad- ,justable head having a plurality -of-spaced tool holders; a source of motionior drivingthe tools; means forming a detachable coupling from the source of motion to a selected tool holder; a transmission mechanism for adjusting the head and including a clutch having separable parts; one of said parts being a bolt movable in a direction parallel to the axis of the clutch and non-rotary until it engages the other part of the clutch; a spring urging said bolt toward engaging position; means movable relative to the bolt in a direction radial of the axis of the clutch for holding the bolt out of engagement; a second spring for urging the said holding means toward holding position; means for causing movement of the holding means away from the holding position and against the force of said second spring; means releasing said movement causing means; said bolt and the holding means having cooperating surfaces such that when the bolt approaches its beginning position after the clutch parts are in enmeans to disengaged position; and stop means joined to the holding means for precisely limiting movement of the transmission.

14. In a machine tool adapted to perform operations on work by the aid of rotary tools: a head having means for holding a plurality of rotary tools; means for moving the head toward and from the work; a shaft; means operated by the shaftofor adjusting the head in step-bystep manner after an operation by a tool is performed; a continuously rotating member on the shaft; a first clutch part connected to the member and having one or more recesses spaced from the axis of the shaft; a cooperating bolt adapted to engage one of the recesses and movable paral lel to the axis of the shaft; said bolt being carried by the shaft; a spring urging the bolt toward engaging position to cause clutching of the shaft to the member; a dog radially movable with respect to the shaft axis and adapted to engage the bolt to restrain the bolt from engaging movement; a second spring urging the dog toward restraining position; and arm connected to the dog; a member for engaging the arm to move the dog out of restraining position against the force of the second spring; means responsive to the movement of the head from the work toward an initial position for operating the said arm engaging member to initiate rotation of the shaft by moving the dog; and means movable by the shaft after the shaft is clutched to the rotating member for moving the arm engaging member to release the dog; said dog and bolt having cooperating surfaces to move the bolt to disengaging position when the shaft moves through a complete revolution.

15. In a machine tool adapted to perform operations on work by the aid of rotary tools: a head having means for holding a plurality of rotary tools; means for moving the head toward and from the work; a shaft; means operated by the shaft for adjusting the head in step-by-step manner after an operation by a tool is performed; a continuously rotating member on the shaft; 9. first clutch part connected to the member and having one or more recesses spaced from the axis ofthe shaft; a cooperating bolt adapted to engage one of the recesses and movable parallel to the axis of the shaft; said bolt being carried by the shaft; a spring urging the bolt toward engaging position to cause clutching of the shaft to the member; a dog radially movable with respect to the shaft axis and adapted to engage the bolt to restrain the bolt from engaging movement; a second spring urging the dog toward restraining position; an arm connected to the dog; a member for engaging the arm to move the dog out 22 of restraining position against the force of the second spring; means responsive to the movement of the head from the work toward an initial position for operating the said arm engaging member to initiate rotation of the shaft by moving the dog; means movable by the shaftafterthe shaft is clutched to the rotatingmember for moving the arm engaging member to release the dog; said dog and bolt having cooperating surfaces to move the bolt to disengaging position when the shaft moves through a complete revolution; and stop means for precisely limiting the movement of the shaft, said stop means being connected to the dog for simultaneous operation therewith. V

16.. In a machine tool adapted to perform operations on work by the aid of rotary tools: a

head having mean for holding a plurality of rotary tools; means for moving the head toward and from'the work; a shaft; means operated by the shaft for adjusting the head in step-by-step manner after an operation by a tool is performed; a continuously rotating member on the shaft; a

firstclutch part connected to the member and rotating therewith; a collar mounted on the shaft; said collar having an annular groove; a second clutch part slidably supported by the collar for movement in adirection parallel to the axis of the shaft for engagement and disengagement with the first clutch part; saidsecond clutch part traversing said groove; means urging said second clutch part toward engaging position; said clutch parts when engaged causing rotation of said shaft; means for restraining the second clutch part against the force of said urging means, said restraining means having an operating portion extending into the groove; means responsive to the movement of the head toward an initial position away from the work for freeing the second clutch part; and means operated upon initiation of the head adjusting movement for releasing the restraining means; said restraining means then contacting the inner wall of the groove; said restraining means and the second clutch part having cooperating surfaces to move the second clutch part out of engaging position when the shaft completes a revolution.

1'7. In a machine tool adapted to perform operations on work by the aid of rotary tools: a head having means for holding a plurality of rotary tools; means for moving the head toward and from the work; a shaft; means operated by the shaft for adjusting the head in step-by-step manner after an operation by a tool is performed; a continuously rotating member on the shaft; a first clutch part connected to the member and rotating therewith; a collar mounted on the shaft; said collar having an annular groove; a second clutch art slidably supported by the collar for movement in a direction parallel to the axis of the shaft for engagement and disengagement with the first clutch part; said second clutch part traversing said groove; means urging said second clutch part toward engaging position; said clutch parts when engaged causing rotation of said shaft; means for restraining the second clutch part against the force of said urging means, said restraining means having an operating portion extending into the groove; means responsive to the movement of the head toward an initial position away from the work for freeing the second clutch part; means operated upon initiation of the head adjusting movement for releasing the restraining means; said restraining means then contacting the inner wall 

